Stock feeder



Nov. 17, 1964 STOCK FEEDER Filed Sept. 24, 1962 G. R. BUNNELL ETAL 3Sheets-Sheet 1 Nov. 17, 1964 G. R. BUNNELL. ETAL sTocK FEEDER 3Sheets-Sheet 2 Filed Sept. 24, 1962 NOV- 17, 1954 G. R. BUNNELL ETALsTocx FEEDER Filed Sept. 24, 1962 El wl United States Patent O 3,151,334srocrs rennen Glenn R. Bnnnell, Dearborn, and Wayne M. Shields,

Bloomfield Township, Mich., assigner-s to Special lingineering Service,lne., Dearborn, Mich., a corporation of Michigan Filed Sept. 24, 1952,Ser. No. 225,911 Ztl Claims. (Cl. 226-150) This invention relates tofluid powered strip stock feeding devices which operate tointermittently advance the stock from one station to another, andparticularly concerns an improved fluid system therefor. rl`hisapplication is a continuation-in-part 'of Serial No. 140,886 tiled byapplicants on September 26, 1961, now abancloned.

ln high speed production manufacturing plants which have operationsrequiring punching, stamping or forming of sheet metal, it is customaryto provide stock feeding apparatus which may be attached to the side ofthe metal working machine or on a table which can be moved next to themachine for gripping the sheet metal stock and feeding the same theretoin intermittent steps. Where the sheet metal stock is provided to theplant in the form of large heavy coils, many problems arise in properlypositioning the sheet metal in the machine and retaining it thereinduring the operation of the machine. It may occur, for example, that astock feeding device does not properly release the stock prior toretraction of its carriage and gripper to their initial operatingpositions which thereby results in pulling of the stock backwardly fromthe machine. lt may also occur that the stock feeding device will beginits stock advancing stroke before the stock is properly gripped andthereby results in improper positioning of the stock in the machine.Moreover, where the weight of the stock coming off of the coil tends topull the stock back out of the stock feeder, it is desirable that somepositive means be provided for preventing release of the stock by thefeeder before the gripper thereof has a lirm hold on the stock.

lt is, therefore, an object of this invention to provide a stock feedingdevice having a uid power system conveniently operable by movingportions of a metal working machine and which insures positive andaccurate positioning of the stock within the machine.

Another object is to provide an actuating iluid system for a stockfeeding device having an air actuated carriage, a stock gripper carriedthereby and a stationary retainer, wherein the system is provided with adouble acting stock feeding motor, and restriction means are providedfor controlling the exhaust from the retracting end of the motor,thereby insuring proper clamping of the stock by the gripper and releaseby the retainer before the stock is advanced, thus eliminating the needfor control of pressure to the advancing end of the stock feeding motorin order to insure proper gripper and retainer action.

A further object is to provide the stock feeding device and fluid systemof the above objects with a stock retaining device which is operable tohold the stock in its advanced position during the retraction of thecarriage and gripper to their initial positions, and which is furtheroperable to release the stock after the gripper has been actuated togrip the stock but before the carriage begins to move toward itsadvanced position.

Further objects, advantages and novel features will become apparent fromthe following description taken in conjunction with the accompanyingdrawings, wherein:

FGURE 1 is a side elevational View of the stock feeding device withportions broken away wherein the carriage of the device and the stockare shown part way through their forward motion;

'ice

FIGURE 2 is a diagrammatic View of the stock feeding device and itsliuid supply system with portions thereof shown in section, wherein thevarious components are shown in position for advancing the carriage andstock;

FiGURE 3 is a partial sectional View of additional valving structure forthe fluid supply system shown in position for exhausting the stockretainer air chamber; and

FlGURE 4 is a diagrammatic View of another embodiment of the inventionwherein the restriction means for delaying advance of the carriage motorcontrols shifting of a valve which controls fluid flow to the retractingend of the carriage motor.

In the drawing, the ends of a base 10 are shown supporting a pair ofhorizontally spaced and parallel carriage rails 11 upon which isslidably mounted a carriage 12. These rails and carriage are assembledon the base by passing the rails first through apertures 13 in one endof the base, then through the bearings 14 in the carriage and then intoapertures 15 in the other end of the base which are aligned withapertures 13. @ne set of these apertures such as 15 may be of such adiameter relative to the diameters of the rails that the rails aretightly frictionally held therein. A gripper 16 is supported on thecarriage and may be partially integrally formed therewith as in acasting operation. A carriage motor comprising a double acting aircylinder 17 is supported by a bracket 18 on the end of thebase and thepiston rod 19 is connected to the carriage 12. A stock retainer 2b ismounted on the other end of the base.

ln further explanation of the basic portions of applicants stock feedingdevice, the cylinder 17 is of the double acting type and is providedwith air ports 21 and 22. These ports allow air to be received by andexpelled from cylinder 17 on opposite sides of piston 24 to provide apower stroke in either direction. Gripper 16 is provided with a piston25 having considerably more effective area than piston 24 and isprovided with a rod 26, the end 27 of which is adapted to grip the sheetmetal stock Z3 which is slid into the laterally extending cavity 29intermediate the bottom 3i) of the gripper and a sliding surface oranvil 31 on carrier 12. A spring 32 returns the piston 25 to an upposition to disengage the shaft 2o from the stock 28 when air isexhausted from the chamber 33 of the gripper through a port 34. Thestock retainer Ztl is of similar construction to gripper 16 and isprovided with a piston 36 which may be of considerably less effectivearea than piston 25 since the function of retainer 2li is merely toprevent the stock from sliding from its position within the press orother machine 37 after the gripper has released its hold on the stock.The piston 36 is provided with a stock-engaging shaft 35i which engagesthe stock and holds it in position on a sliding surface or anvil 39 onbase lil. A return spring 4h returns the piston to its up position whenair is exhausted from the chamber 41 through the line 95.

The air system for supplying actuating air to cylinder 17, gripper 16,and retainer 2t), and for exhausting air therefrom comprises a 4-Wayvalve 44, a pressure responsive exhaust valve 45, and a check valve 46.An air flow control valve i3 may also be provided to enhance theoperation of the system in a manner to be hereinafter described.

The valve 44 is provided with a reciprocal valve plunger 27, an airinlet port 48 communicating directly with passages 49 and Sil, a pair ofpassages 51 and 52 providint7 ports 53 and 54, respectively, and a pairof exhaust passages 55 and 56. The plunger 47 is provided with a pair ofcircumferential grooves 57 and 58 which are adapted to connect theconduits 51 and 52, respectively, to inlet i3 and to exhaust passages 55and 56.

l An, actuatingrarm 59` is pivotally mounted. at 6i? to an It end plate61 attached to the valve body and engages the end of plunger 47 to movethe same to the right against the action of a spring 62. The arm isactuated when a roller 63 on the end thereof is engaged by a cam 64 onthe press ram 65 which pivots the arm 59 in a counterclockwise directionwith respect to FIGURE 2.

The pressure responsive exhaust valve 45 comprises a body 66 having abore therein forming a chamber 67 slidably receiving a piston 68. Aspring 72 urges the piston to an up position so as to connect an airconduit 745 to an air conduit 76 which is connected through an air bleedor exhaust port 77 adjustable by a needle valve 78 threadedly receivedin boss 79.

Check valve 46 is provided with a seat Si), a ball 81, and a spring 82.This arrangement allows air flow through the check valve to the left butnot to the right. Check valve 46 is threadedly received into a conduitjoining member 83 provided with a passageway 84 connected to the passage74.

The air flow control valve 43 comprises a body 86 having a passage 87therein provided With two orifices 88 and S9. A needle valve 9) adjuststhe size of orifice 88 to regulate the ow of air to the left withrespect to FIG- URE 2, and the port 89 is engaged by a lightlyspringurged bail 91 which allows substantially free air flow through thevalve to the right but not to the left. This type of valve is well-knownand is available under the name of Pneu-Trol, which is a registeredtrade name of Auto-Ponents, Inc., of Bellwood, Illinois.

In the operation of the air system and the stock feeding device, air issupplied under pressure preferably from about 8O to about 100 p.s.i. toa filter 92, air flow regulator 93, and an oil-type of air lubricator 94from which the air is then conveyed Athrough a suitable air line to theinlet port 48 of the valve 44. After the press ram has been activated toperform Work on the stock 28 as shown in FIGURE l and the press ram 65and cam 64 have been retracted to their up position, plunger 47 isforced to the left as shown in FIGURE 2 to connect the retracting sideor chamber 96 of cylinder 17 to exhaust passage 56 through a conduit 95.The tlow control valve 43 regulates the rate at which chamber 96 isexhausted to thereby control the speed of forward motion of piston 24and carriage 12. Chamber 41 of the retainer 2t) is simultaneouslyexhausted through line 95 and the small size of this chamber and thespring 4i) allow the shaft 38 to rapidly release the stock prior to anyforward motion of piston 24 to thereby prevent any buckling of the stockdue to premature actuation of piston 24 to the left. A more positiveacting means for exhausting chamber 41 is hereinafter described.

Simultaneously with the exhausting of chamber 96, the advancing side orchamber 97 of cylinder 17 is connected through the conduit 98 to theinlet 48 of valve 44. Ball 81 allows free passage of air to chamber 97and piston 68 blocks the exhaust passages 74, 76. At the same time,chamber 33 of the gripper 16 is connected by conduit 93 to inlet 48, andthe relative effective areas of pistons 24, 25, and 36 and the properlyselected sizes of springs 32 and 4t), the controlled exhaust of chamber96, and the inertia of carriage 12 all combine to allow proper clampingof the stock by the gripper priorto the complete release of the stock byretainer 2i) and forward movement of the carriage.

After the carriage has completed its forward movement to the left, thepress ram is actuated downwardly and the cam 64 strikes roller 63 toactuate the valve plunger 47 to the right in FIGURE 2. Chamber 41 ofretainer 26 and chamber 96 of cylinder 17 are thereupon connected toinlet 48 by line 95, and ball 91 of valve 43 retracts against its springto allow the free low of air into chamber 96. As retainer 20 is actuatedto clamp the stock, charnber 33 of gripper 16 is exhausted and when theair pressure therein reaches a predetermined value, the piston 68 ofvalve 45 moves upwardly to connect chamber 97 of cylinder 17 to exhaustport 77. The spring 72 and the size of piston 68 must be considered indetermining the aforesaid predetermined pressure. It is noted, however,that the sizes of piston 25 and spring 32 also are factors indetermining this predetermined pressure since it must be assured thatthe gripper has released the stock at this pressure, The rate of exhaustof chamber 97 and the retraction rate of the carriage are regulated bythe needle valve 7S.

When the press ram again moves upwardly to disengage carn 6d from roller63, plunger 47 is again moved to the left to cause the gripper to againgrip the stock and the retainer 2t) to release it, and to cause thecarriage and stock to again be advanced to the press.

By the connection of another pressure responsive exhaust valve andanother check valve in a proper manner to the stoel; retainer 20 and togripper 16, it is also possible to positively coordinate the actions ofthe retainer 20 and the gripper 16 to insure that the retainer does notrelease the stock prior to the gripping thereof by the gripper.

This may be accomplished by connecting a check valve 160 into the branch161 of line 95 so that the inlet 102 of the valve communicates directlywith feed line 95, and the outlet 193 of the valve directly with chamber41. The chamber' 41 is also connected by the passages 104- and 105 tothe cylinder 106 of a prcssure responsive exhaust valve 167 whichcylinder is connected to the air supply line 93 of gripper 16. Anexhaust port 168 adjustable in size by needle valve 110 communicateswith cylinder 106 and allows chamber 41 of the retainer to exhaust whenthe pressure in line 98 is sufficient to force piston 112 downwardlyagainst the force of spring 114 to align the peripheral groove 116 inthe piston with passages 195 and 120. The relative sizes of the springs32, 4t), and 114, and the relative sizes of pistons 25, 36, and 112 areso selected that the gripper rmly grasps the stock before the retainerreleases it.

FIGURE 4 shows another embodiment of the invention in which restrictionmeans are provided for controlling a valve which in turn controls tlowof fluid to and from the retracting end of the carriage motor. A controlvalve is generally indicated at 291, this valve being similar in natureto valve 44- of the previous embodiment and having a supply port 292,exhaust ports 203 and 204, two working ports 295 and 266 and a spool 207which is normally in the left-hand position shown in FIGURE 4 but isshiftable to the right by a cam-operated lever 29S. It will beunderstood that other means, such as a solenoid (not shown) controlledby a cam-operated switch, could be utilized to shift spool 267.

A carriage motor generally indicated 269, a gripper motor generallyindicated 211, and a retainer motor generally indicated at 212 are alsoprovided as in the previous embodiment. Working port 265 is directlyconnected to the advancing end 213 of carriage motor 209 and to grippermotor 211 by a conduit 214 having branches 215 and 216, respectively.Working port 206 is directly connected to retainer motor 212 by aconduit 217 having a branch 21S. A connection to the retracting end 219of carriage motor 239 is provided by a branch 221 leading from conduit217 through a check valve 222 which permits flow to but not from a port223 of a 3-way auxiliary valve generally indicated at 224. Valve 224 hasa spool 225 which is urged to a normal right-hand position by a spring226, the valve when in this right-hand position connecting port 223 to aport 227 which leads to a conduit 22S connected to retracting end 219 ofmotor 269. When pressure is applied to a chamber 229 at the end of spool225 opposite spring 226, the spool is shifted to its left-hand positionas shown in FIGURE 4, in which position port 223 is cut otf from port227, and the latter is connected to an exhaust port 231.

A branch conduit 232 leads from conduit branch 215 to a port 233 forchamber 229. First and second variable restrictions 234 and 236,respectively, are disposed in series in branch conduit 232. A bypass 237for restriction 234 has a check valve 238 permitting dow only from port23.3 toward branch conduit 215. A bypass 239 for restriction 236 has acheck valve 241 permitting flow only from branch conduit 215 toward port233.

In operation of the embodiment of FIGURE 4, assuming an initialcondition in which the press is retracted and spool 267 of valve 201 isin the left-hand position as shown in FIGURE 4, pressure will beimmediately applied to gripper motor 211 and to the advancing end 213 ofcarriage motor 2M. Valve 224. will initially be in its right-handposition, with port 227 connected to port 223 and when in this position,iuid cannot leave the retracting end 219 of carriage motor 269, becauseof the presence of check valve 222 which blocks escape of the fluid, andthe carriage motor will therefore be prevented from advancing. However,fluid will iiow from branch conduit 215 through restriction 234 andcheck valve 2451 to valve chamber 229, and when the pressure in chamber229 has built up suliiciently to overcome spring 226, spool 225 willshift to the left, connecting port 227 to exhaust port 231. Uponconnection of retracting end 219 of carriage motor 209 to exhaust, thepressure in advancing end 213 of motor 269 will cause the carriage motorto advance. By this time, gripper motor 211 will have been moved to itsgripping position and retainer motor 222 will have been moved to itsretracted position since port 2% is connected to exhaust. It willtherefore be assured that the advancing of stock 242 will take placeonly after the stock has been properly gripped by gripper motor 211 andreleased by retainer motor 212.

After the carriage has completed its forward movement to the left, thepress ram is actuated downwardly and spool 207 of valve 201 is shiftedto the right. This will cause supply port 2ll2 to be connected toWorking port 266, while Working port 2&35 is connected to exhaust port203. Pressure will be immediately supplied to retainer motor 212,clamping stock 242 in its advanced position. Pressure will also beimmediately released from gripper' motor 211, causing it to move to itsretracted position.

The advancing end 213 of carriage motor 269 will be immediatelyconnected to exhaust. However, pressure will not be immediately appliedto retracting end 219 of carriage motor Zilli, since valve spool 225 ofvalve 224 Will be initially in its left-hand position as shown in FIG-URE 4. Fluid Will flow from chamber 229 through restriction 235 andcheck valve 235, and when the pressure in chamber 229 has beensuliiciently depleted, spring 22e will shift valve spool 225 to theright, connecting ports 223 and 227. This will permit pressure to beapplied to retracting end 219 of carriage motor 209, and the carriagewill be retracted. It is tnus assured that carriage retraction will notoccur until stock 242 is properly clamped by retainer motor 212, andgripper motor 211 has been moved toits retracted position.

While it will be apparent that the preferred embodiments hereinillustrated are well calculated to fulfill the objects above stated, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

l. In a stock feeder, a reciprocable carriage, a double acting pistonmotor for advancing and retracting said carriage, a gripper on saidcarriage, a single acting piston motor for moving said gripper to agripping position, resilient means urging said gripper to a retractedposition, means for simultaneously applying liuid pressure to saidgripper motor and the advancing end of said carriage motor, said grippermotor having a substantially greater effective area than said advancingend of the carriage motor, means for exhausting said gripper motor andapplying pressure to the retracting end of said carriage motor, and avalve coacting with one end of said carriage motor, said valve beingmovable to a irst position in re- 6 sponse .to application of pressureto said gripper motor for preventing retraction of said carriage motorbut being movable to a second position in response to diminution ofpressure at said gripper motor for permitting 4retraction of saidcarriage motor.

2: In a stock feeder, a reciprocable carriage, a double acting pistonmotor for advancing and retracting said carriage, a gripper on saidcarriage, a single acting piston motor for moving said gripper toagripping position, resilient means urging said gripper lto a retractedposition, means for simultaneously applying fluid pres-sure to saidgripper motor and the advancing end of said carriage motor, said grippermotor having a substantially greater effective area than said advancingend of the carriage motor, means for exhausting said gripper motor andapplying pressure to the retracting end or" said carriage motor, a valvefor blocking iiuid iiow from the advancing end of said carriage motor,and resilient means responsive to diminution of pressure at said grippermotor for moving said blocking means to an unblocking position, wherebyretraction of said carriage motor will be permitted.

3. in a stoclr feeder, a reciprocable carriage, a double acting pistonmotor for advancing and retracting said carriage, a gripper on saidcarriage, a. gripper motor for causing said gripper to move to agripping position, a first line leading to the advancing of saidcarriage motor, a second line leading to the retracting end of saidcarriage moto-r, a third line leading to said gripper motor, means forsimultaneously pressurizing said second line and connecting said firstand third lines to exhaust, a check valve in said first line permittingflow only to the advancing end of said cmriage motor, an exhaust tap inIsaid first line between said check valve and the advancing end of saidcarriage motor, a blocking member in said tap movable to a blockingposition in response to fluid pressure at said gripper motor, and meansresponsive to diminution of pressure at said gripper motor for movingsaid blocking member to an unblocking position whereby the advancing endof said carriage motor will be connected to exhaust.

4. The combination according to claim 3, said exhaust tap being furtherprovided with an adjustably restricted orifice.

5. In a stock feeding device, a reciprocable carriage, a piston motorfor advancing said carriage, a gripper on said carriage, a gripper motorfor moving said gripper to a gripping position, means for simultaneouslyapplying iiuid pressure from a common source to said motors, theffective area of said gripper motor means being substantially greaterthan the effective area of said carriage motor, means for connecting thecarriage and gripper motors to exhaust, and an adiustably restrictedorifice in the carriage motor exhaust connection.

6. ln a stock feeding device, a reciprooable carriage, a fluid motor foradvancing `and retracting said carriage, a gripper on said carriage, apiston motor for moving said gripper to a gripping position, a stockretainer, -a piston motor for moving said stock retainer to a retainingposition, an exhaust conduit for said retainer piston motor, and ablocking member in said exhaust conduit having a normal blockingposit-ion but responsive to application of pressure to said gripperpiston motor for moving to an unbloclcing position permitting exhaustionof said retainer piston motor.

7. The combination according .to `claim 6, further pro'- vided with anadjustably restricted orifice in said exhaust conduit.

8. In a stock feeder, a reciprocable carriage, a piston motor foradvancing said carriage, a gripper on said carriage, a piston motor formoving said gripper to a gripping position, means for simultaneouslyapplying flu-id pressure to `said motors, the effective area of saidgripper motor being substantially greater than the effective `area ofsaid carriage motor, ya stock retainer, a piston motor for moving saidstock retainer to a retaining posi- 7 tion, an exhaust conduit for saidretainer motor, a blocking member in said exhaust conduit having anormal blocking position, and means responsive to application ofpressure to said gripper motor for moving said blocking member to anunblocking position.

9. In a stock feeder, a reciprocable carriage, a double acting pistonmotor for advancing and retracting said carriage, a gripper on saidcarriage, a piston motor for moving said gripper to a gripping position,a stock retainer, a piston motor for moving said stock retainer to aretaining position, means for simultaneously applying pressure to theadvancing end of said carriage motor and `to said gripper motor and forexhausting the retracting end of said carriage motor and said retainermotor, the effective area of said gripper motor being substantiallygreater than the effective area of the advancing end of said carriagemotor, the effective area of said retainer motor being substantiallysmaller than the effective area of the `advancing end of said carriagemotor, an adjustably restricted `oriiice in the exhaust connection forthe retracting end of said carriage motor, means for preventingexhausting o-f said retainer motor until pressure has been applied tosaid gripper motor, means for simultaneously applying pressure to theretracting end of said carriage motor and to said retainer motor and forconnecting the advancing end of said carriage motor and said grippermotor to exhaust, said last-mentioned means including means for delayingthe exhausting of said advancing end of the carriage motor untilpressure has been depleted at gripper motor, and an adjustablyrestricted orifice in the exhaust connection for the advancing end ofsaid carriage motor.

10. In a stock feeder, a reciprocable carriage, a double acting fluidactuated carriage motor for advancing and retracting said carriage, areciprocable gripper on said carriage, a fluid actuated gripper motorfor moving said gripper to a gripping position, means for simultaneouslyapplying pressure to the advancing end of said carriage motor and tosaid gripper motor for moving said gripper to a gripping position, anexhaust connection for the retracting end of said carriage motor, andrestriction means for controlling the flow of fluid from the retractingend of said carriage motor to said exhaust connection, whereby saidsimultaneous application of pressure will cause said gripper to move toits gripping position before said carriage advances.

11. In a stock feeder, a reciprocable carriage, a double tacting iiuidactuated carriage motor for advancing and retracting said carriage, astock retainer, a fluid actuated retainer motor for moving said stockretainer to a retaining position, means for simultaneously supplyingiiuid under pressure to the advancing end of said carriage motor andconnecting said retainer motor to exhaust, an exhaust connection for theretracting end of said carriage motor, and restriction means forcontrolling the flow of fluid from the retracting end of said carriagemotor to said exhaust connection, whereby said retaining motor will beconnected to exhaust before said carriage advances.

12. In a stock feeder, a reciprocable carriage, a double acting fluidactuated carriage motor for advancing and retracting said carriage, areciprocable gripper on said carriage, a fluid actuated gripper motorfor moving said gripper to a gripping position, a stock retainer, afluid actuated retainer motor for moving said retainer to a retainingposition, means for simultaneously supplying fluid under pressure to theadvancing end of said carriage motor and to said gripper motor andconnecting said retainer motor to exhaust, 'an exhaust connection forthe retracting end of said carriage motor, and restriction means forcontrolling the flow of uid from the retracting end of said carriagemotor to said exhaust connection, whereby said gripper will be moved toits gripping position and said retainer motor will be connected toexhaust before said carriage advances.

13. In a stock feeder, a reciprocable carriage, a double acting iiuidactuated carriage motor for advancing and retracting said carriage, areciprocable stock gripper on said carriage, a fluid actuated grippermotor for moving said gripper to a gripping position, means forsimultaneously applying pressure to the advancing end of said carriagemotor and to said gripper motor, means for simultaneously connecting theadvancing end of said carriage motor and said gripper motor to exhaust,and means for applying fluid pressure `to the retracting end of saidcarriage motor a predetermined time after the advancing end of saidcarriage motor and said gripper motor have been connected to exhaust.

14. The combination according to claim 13, said lastmentioned meanscomprising a pressure connection for the retracting end of said carriagemotor, a valve in said last-mentioned connection, means responsive toapplication of pressure to the advancing end of said carriage motor formoving said valve to a position closing said connection, and time delaymeans responsive to connection of the advancing end of said carriagemotor to exhaust for moving said valve to a position opening saidconnection.

15. The combination according to claim 14, said time delay meanscomprising a variable restriction and a check valve in parallel relationbetween said valve and the advancing end of said carriage motor.

16. In a stock feeder, a reciprocable carriage, a double acting fluidactuated carriage motor for advancing and retracting said carriage, areciprocable stock gripper on said carriage, a fluid actuated grippermotor for moving said gripper to a gripping position, means forsimultaneously applying pressure to the advancing end of said carriagemotor and to said gripper motor, said gripper motor having asubstantially greater effective area than said advancing end of thecarriage motor, means for simultaneously connecting the advancing end ofsaid carriage motor and said gripper motor to exhaust, and means forapplying fluid pressure to the retracting end of said carriage motor apredetermined time after the advancing end of said carriage motor andsaid gripper motor have been connected to exhaust.

17. In a stock feeder, a reciprocable carriage, a double acting uidactuated carriage motor for advancing and retracting said carriage, areciprocable gripper on said carriage, a iluid actuated gripper motorfor moving said gripper to a gripping position, a stock retainer, a.fluid actuated retainer motor for moving'said stock retainer to aretaining position, control valve means having a supply connection, anexhaust connection, and first and second working ports, said controlvalve means having a first position in which said supply port isconnected to said first working port and said second working port isconnected to exhaust, and a second position in which said supply port isconnected to said second Working port and said first working port isconnected to exhaust, means connecting said first working port directlyto the advancing end of said carriage motor and to said gripper motor,means connecting said second working port directly to said retainermotor, auxiliary valve means having a first port connected to theretracting end of said carriage motor and a second port, a connectionbetween the second port of said control valve means and the second portof said auxiliary valve means, a check valve in said 1astmentionedconnection permitting ow only from said control valve means to saidauxiliary valve means, an exhaust port in said auxiliary valve means,the auxiliary valve means being movable between a first position inwhich said retracting end of the carriage motor is connected to exhaustand a second position in whichthe retracting end of said carriage motoris connected to the second port of said control valve means, a pistonchamber pressurizable to move said auxiliary valve means to its firstposition, and a connection between the first port of said control valvemeans and said piston chamber.

18. The combination according to claim 17, further provided with arestriction in said last-mentioned con- 9 1@ nection, and a bypass forsaid restriction having means only away from said piston chamber, andmeans in the permitting ow only away from said piston chamber. otherbypass permitting flow only toward said piston 19. The combinationaccording to claim 17, further chamber. provided with a restriction insaid last-mentioned con- References Cited in the me of this patentnection, and a bypass for said restriction having means 5 permittingflow only toward said piston chamber. UNITED STATES PATENTS 20. Thecombination according to claim 17, further 2,622,874 Haller Dec. 23,1952 provided with rst and second restrictions in series in 2,704,081Lindsay Mar. 15, 1955 said last-mentioned connection, a bypass for eachof said 2,978,160 Bunnell Apr. 4, 1961 restrictions, means in one ofsaid bypasses permitting flow 10 3,038,645 Nordlof lune 12, 1962

5. IN A STOCK FEEDING DEVICE, A RECIPROCABLE CARRIAGE, A PISTON MOTORFOR ADVANCING SAID CARRIAGE, A GRIPPER ON SAID CARRIAGE, A GRIPPER MOTORFOR MOVING SAID GRIPPER TO A GRIPPING POSITION, MEANS FOR SIMULTANEOUSLYAPPLYING FLUID PRESSURE FROM A COMMON SOURCE TO SAID MOTORS, THEEFFECTIVE AREA OF SAID GRIPPER MOTOR MEANS BEING SUBSTANTIALLY GREATERTHAN THE EFFECTIVE AREA OF SAID CARRIAGE MOTOR, MEANS FOR CONNECTING THECARRIAGE AND GRIPPER MOTORS, TO EXHAUST, AND AN ADJUSTABLY RESTRICTEDORIFICE IN THE CARRIAGE MOTOR EXHAUST CONNECTION.